Steve Mason is sitting in a Vietnamese restaurant in Shoreditch, describing some of the responses he received last December when he released the track Fight Them Back, a swaggering call to arms which advocates combating the powers-that-be with "a fist, a boot and a baseball bat".

"I've had panicking tweets from fans saying: 'Is the whole album political?'" he says with a dry smile. "They think it'll be me chanting over a hip-hop beat going: 'Everything's crap. Everything's rubbish.'"

Born in Fife 40 years ago, Mason is old enough to remember when songwriters routinely expressed political opinions and to be frustrated that such a message is now usually seen as an embarrassment or an imposition. He recalls with dark amusement the time, in 2001, when his old group the Beta Band were supporting Radiohead and he encouraged several thousand Texans to shoot President Bush. "Radiohead didn't like that at all. Neither did our American management." I don't imagine the Texans were crazy about it. "No."

Fight Them Back is Mason's first truly unapologetic protest song but, no, his new album, Monkey Minds in the Devil's Time, isn't all like that. In fact it's no less autobiographical than Mason's previous album, 2010's Boys Outside. Enriched by evocative instrumental interludes, it's a frequently beautiful account of personal and political awakening. "It's a concept album," he says. "I'm just going to come out and say it. I imagine people listening to it on those big 70s headphones with the curly lead."

At one time a notoriously thistly interviewee – one traumatised writer described him as "addressing journalists as if they're covered in dung" – Mason is now keen to be understood. His body language suggests discipline and containment. He eats his curry with fastidious care and the blue hardback lyric book that he shows me is the neatest I've ever seen. His wry humour is no longer weaponised.

The discipline might stem from the years he spent studying kung fu with Shaolin monks. The Buddhist-inspired album title certainly does. "A monkey mind is a mind that's young and agitated and cannot concentrate," he explains. "Human beings are taking in information all the time, from everything. You're so bombarded and bamboozled."

Mason cannot precisely define his political beliefs and has never voted ("a largely pointless exercise") but he says: "I struggle to think of any part of our daily lives that capitalism hasn't touched in a negative way." Although he attended a major anti-capitalist demonstration outside parliament back in 2000 – he claims he was one of those who gave Winston Churchill's statue an impertinent turf Mohawk – he's grown disillusioned with the predictable ritual of marches.

His more insurrectionary ideas, meanwhile, faded when he was staying in Hackney in summer 2011 and witnessed the riots first-hand. "You realised how ridiculously unfocused it was. Local communities got smashed to bits, people got hurt, and it achieved absolutely nothing except creating more fear in those communities. It was heartbreaking. I don't think rioting is the answer any more."

So what about Fight Them Back? "Those lyrics are wrong," he laughs. "You can't fight back with violence. I used to think like that but it's very naive. They're ready for that shit. You have to find a different way to beat them. It's paper scissors stone."

He thinks it's more important to modify your own behaviour, whether by educating yourself about politics, donating your time and money to those in need, or just sticking to your principles. The Beta Band, he says, always tried to operate according to certain values.

"For me it was always a political band," he says. "We stood for never being sucked into the machine. The other members weren't particularly enamoured of me talking politics so I tended not to. But a political statement doesn't mean you're wearing a bandana and throwing a petrol bomb. A political statement can be a beautiful thing, you know?" He shrugs. "For me that's what it was. I think the rest of the band would certainly disagree."

With their remarkable first three EPs, which effortlessly blended dance music, hip-hop, folk and rock, the Beta Band became Britain's most exciting new band in the late 90s – a rare point of musical agreement between Radiohead and Oasis. But they acquired a reputation for being difficult to the point of self-sabotage, which made more sense when Mason later revealed that he had been suffering from appalling depression.

Sinking most of their earnings into impractically ambitious live shows, the band lived on diminishing wages. When Mason unilaterally pulled the plug in 2004, they owed EMI £1.2m, having turned down about the same amount in advertising deals. "We were being offered large chunks of money to do adverts once again and it was so tempting because we were fucked. So I knew it had to end."

Mason's militant principles must have been hard, I suggest, for the other members. "A nightmare," he agrees. "Especially when you throw depression into the mix. I don't envy them at all. But every good band needs a fascist dictator. All the best ideas have a purity to them, and the more that idea is diluted, I mean, you might just as well be Oasis, you know?"

The next few years were difficult. His old bandmates ostracised him (they're on good terms now), and his depression worsened. In 2006 he experienced what he described as "a monumental breakdown" and went awol for two weeks. Medication and hypnotherapy set him on a more even keel. He regrets once resisting antidepressants for fear they would blunt his songwriting. "What I found was that you can either write songs or you can't. I wasn't going to die for people's entertainment. I wasn't going to ruin every single relationship in my life for music. I felt like I was 21 until I was about 34. Everything was live or die. It was all about extremes, and that's a very inefficient way to live."

Monkey Minds may be about apathy, poverty and riots but it is also about becoming the person you want to be. The warmly affecting new single Oh My Lord, says Mason, is about "that terrible pitfall that a lot of people my age fall into where you start to feel that you've done everything you're ever going to do, and all you can do is plod along and have your memories. And fuck that, you know? Fuck that."

Monkey Minds in the Devil's Time is out on Domino Records tomorrow. Steve Mason plays three UK dates (Glasgow, Manchester and London) in April